I'm using Dayjs, typescript.
I want to use like this
export class CustomDate extends dayjs.Dayjs {
format() {
}
}
It returns 'TypeError: Class extends value undefined is not a constructor or null'.
When I searched this, the reason occured this problem is circular dependency, but I cannot understand it...
is it incorrect way?
I dug though the source for a bit, and I think this will work. However, since dayjs doesn't officially support sub-classing, I wouldn't recommend doing this.
(You might have to keep digging through the source code though: https://github.com/iamkun/dayjs/blob/4a7b7d07c885bb9338514c234dbb708e24e9863e/src/index.js)
/* Extracting the underlying Datejs class */
const Dayjs_proto = Object.getPrototypeOf(dayjs());
const Dayjs = Dayjs_proto.constructor;
Dayjs.prototype = Dayjs_proto;
class CustomDate extends Dayjs {
constructor(date) {
super({
date: date,
args: arguments,
});
}
format() {
}
}
const myCustomDateObject = new CustomDate(new Date());
console.log(myCustomDateObject);<script src="https://cdnjs.cloudflare.com/ajax/libs/dayjs/1.10.7/dayjs.min.js"></script>